Short overview of parametric loudspeakers array technology and its implications in spatialization in electronic music

UID/EAT/00472/2013In late December of 1962, a Physics Professor\from Brown University, Peter J. Westervelt,\submitted a paper called Parametric Acoustic Array considered primary waves interacting within a given volume and calculated the scattered pressure field due to the non-linearities within a small portion of this common volume in the medium. Since then, many outputs of this technology were developed and applied in contexts such as military, tomography, sonar technology, artistic installations and others. Such technology allows perfect sound directionally and therefore peculiar expressive techniques in electroacoustic music, allowing a very particular music dimension of space. For such reason, it’s here treated as a idiosyncrasy worth to discuss on its on terms. In 2010-2011 I composed the piece "A Anamnese das Constantes Ocultas", commissioned by Grupo de Música Contemporânea de Lisboa, that used a parametric loudspeakers array developed by engineer Joel Paulo. The same technology was used in the 2015 acousmatic piece “Jeux de l'Espace ” for eight loudspeakers and one parametric loudspeaker array. This paper is organized as follows. A theoretical framework of the parametric loudspeaker array is first introduced, followed by a brief description of the main theoretical aspects of such loudspeakers. Secondly, there is a description of practices that use such technology and their applications. The final section describes how I have used it in my music compositions.publishersversionpublishe

Ультразвуковий пристрій формування силової дії в повітрі

Метою роботи є аналіз сучасної техноголії створення акустичного пристрою формування силової дії в повітрі та створення ультразвукового офтальмологічного масажеру. В роботі проведено розрахунок ефективності технології створення силової дії в повітрі за допомогою ультразвуку, базуючись на роботах та методах отримання силової дії ультразвуку в повітрі Козерука С.О., Розенберг Л.Д, T.Гоші., M.Такахаші, T.Івамото. Проведено аналіз шкідливості та доцільності використання ультразвуку в офтальмології. Визначені оптимальні технічні характеристики для пристрою, а саме ультразвукового масажера для ока. В результаті теоретичних підрахунків та результатів, отриманих після моделювання процесу роботи пристрою в середовищі програмування Matlab та їх оцінки, було виявлено, що технологія формування силової дії в повітрі є потенційною і перспективною для створення офтальмологічного масажера. Розроблено пристрій та зроблено ескізне проектування.The purpose of the work is to analyze the modern technology of creating an acoustic device for the formation of force in the air and the creation of an ultrasound ophthalmic massager. In this work, the efficiency of the technology of creating force in the air by means of ultrasound is carried out, based on the work and methods of obtaining the force action of ultrasound in the air Koseruka S.O., Rosenberg L.D., T.Goshi, M.Takahashi, T.Ivamoto. The analysis of harmfulness and expediency of use of ultrasound in ophthalmology is carried out. The optimum technical specifications for the device, namely the ultrasonic massager for the eye, are determined. As a result of theoretical calculations and the results obtained after simulating the operation of the device in the Matlab programming environment and their evaluation, it was discovered that the technology of formation of force in the air is potential and promising for the creation of an ophthalmic massager. The device was developed and sketch design was done

Investigating the Feasibility of Using Focussed Airborne Ultrasound as Tactile Feedback in Medical Simulators

Novice medical practitioners commonly practice on live patients in real medical procedures. However, due to the inexperience of the practitioner, mistakes are likely which exposes the patient to undue risk. To improve the training of novices, medical simulators create a virtual patient providing a safe environment for the user to practice within. An important clinical skill is palpation, a physical examination technique. The practitioners use their hands to feel the body of the patient to make diagnosis. A virtual patient has a visual representation but as it is virtual, the patient is not physically present. Haptics technology provide additional benefits to the training session by stimulating the physical sense of touch. A novel technique has recently emerged for stimulating tactile sensation called acoustic radiation pressure from focussed airborne ultrasound. Acoustic radiation creates a focal point of concentrated acoustic pressure in a three-dimensional field producing a force in mid-air. Airborne ultrasound has several advantages over conventional technologies. It was also initially theorised that using airborne ultrasound to simulate palpation compared to a previous system called PalpSim which consists of a rubber tube filled with water permanently embedded in a block of silicone, will offer better controllability over the displayed sensation to simulate various tactile sensations. The thesis has investigated the feasibility of using focussed airborne ultrasound as tactile feedback in medical simulators. A tactile device called UltraSendo was completely custom built to simulate an arterial pulse and a thrill sensation. UltraSendo was integrated with an augmented reality simulator displaying a virtual patient for user interaction. The simulator was brought to Ysbyty Glan Clwyd hospital for user feedback. A wide range of user responses were gathered. The majority of responses felt the arterial pulse was not sufficiently realistic whilst there were higher ratings for the thrill sensation which is acceptably realistic. Positive feedback suggests that airborne ultrasound can indeed provide tactile feedback in a medical context and is better at simulating a thrill sensation compared to a pulse sensation

Imagining & Sensing: Understanding and Extending the Vocalist-Voice Relationship Through Biosignal Feedback

The voice is body and instrument. Third-person interpretation of the voice by listeners, vocal teachers, and digital agents is centred largely around audio feedback. For a vocalist, physical feedback from within the body provides an additional interaction. The vocalist’s understanding of their multi-sensory experiences is through tacit knowledge of the body. This knowledge is difficult to articulate, yet awareness and control of the body are innate. In the ever-increasing emergence of technology which quantifies or interprets physiological processes, we must remain conscious also of embodiment and human perception of these processes. Focusing on the vocalist-voice relationship, this thesis expands knowledge of human interaction and how technology influences our perception of our bodies. To unite these different perspectives in the vocal context, I draw on mixed methods from cog- nitive science, psychology, music information retrieval, and interactive system design. Objective methods such as vocal audio analysis provide a third-person observation. Subjective practices such as micro-phenomenology capture the experiential, first-person perspectives of the vocalists them- selves. Quantitative-qualitative blend provides details not only on novel interaction, but also an understanding of how technology influences existing understanding of the body. I worked with vocalists to understand how they use their voice through abstract representations, use mental imagery to adapt to altered auditory feedback, and teach fundamental practice to others. Vocalists use multi-modal imagery, for instance understanding physical sensations through auditory sensations. The understanding of the voice exists in a pre-linguistic representation which draws on embodied knowledge and lived experience from outside contexts. I developed a novel vocal interaction method which uses measurement of laryngeal muscular activations through surface electromyography. Biofeedback was presented to vocalists through soni- fication. Acting as an indicator of vocal activity for both conscious and unconscious gestures, this feedback allowed vocalists to explore their movement through sound. This formed new perceptions but also questioned existing understanding of the body. The thesis also uncovers ways in which vocalists are in control and controlled by, work with and against their bodies, and feel as a single entity at times and totally separate entities at others. I conclude this thesis by demonstrating a nuanced account of human interaction and perception of the body through vocal practice, as an example of how technological intervention enables exploration and influence over embodied understanding. This further highlights the need for understanding of the human experience in embodied interaction, rather than solely on digital interpretation, when introducing technology into these relationships